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Help with Crank position sensor problem

4K views 3 replies 2 participants last post by  bigdog0u81 
#1 ·
I'm very new to this forum and may not know the proper way to post, but I'll give it a try.
I have a 2011 jetta tdi with 240,000 miles. Getting a code for engine speed sensor (G28) 000802 no signal. It was dignosed at the dealer where they said it needed the engine speed sensor replaced. Should also mention it has lack of power, I would imagine it's in limp mode. So, I replace the sensor and cleared the code and now it starts and idles fine but as soon as I stsrt to drive it stumbles and the same code returns. I've repeated this process a few times, clearing the code, restarting, letting it idle for awhile and then start driving. It consistently does the same thing each time.
Does anyone have info on checking circuit integrity, what should I see for voltages on which wires? Anyway to check the sensor itself for proper resistance? Other then that are there other issues to look for besides the possibility of the sensor not being installed right?
I should mention that a few months ago i did a flywheel replacement and also replaced the rear main seal. I used the proper installation tool and it was running fine up until now so I wasn't suspecting anything wrong with that part.
Any help or suggestions would be greatly appreciated, and thank you so much for being there.
 
#2 ·
I'm assuming no one has a clue about this issue. I'll update my findings and hopefully someone may know something.
I did find wiring diagrams and did some testing. What I have at the harness is the same as the cam sensor, 5v ref, 5v signal and a ground. I was unsure of whether there should be voltage on the signal wire with the harness unplugged, someone on you tube, (vw shop) thought there shouldn't be and said if there was it may mean the signal and reference wires are shorted together. However, the cam sensor harness is exactly the same and I tested all the wires back to the ECU and everything seems to be fine for all three.
So, thinking I might have had a bad new sensor, I bought another one and replaced it again. Same thing, although, the crank is extended at every start up and the code for no singal is thrown just before it starts. There is no RPM being registered on the tach and the scan tool during cranking, only once it starts. So, the question is, is the sensor not sending a signal or is the ECU not seeing it? Unfortunately I don't own a lab scope to see whether it is sending a signal while cranking. Any help at all would be greatly appreciated.
 
#3 ·
I htought I would post the outcome of my crank position sensor issue for the sake of anyone else who may have this problem in the future. It is a little difficult to believe that no one on this forum had any input what so ever since I didn't get even one response. Anyway the problem was not the sensor itself but the reference and signal wires were shorted,which is what caused the original issue. After handling the harness from taking things apart a few times, finally the reference wire completely broke, which I was able to figure out by checking continuity from the sensor connector back to the ecu. Then it was just a matter of finding the exact location of the broken wire. What threw me off in the beginning, is that I had 5volts on both the reference and signal wires, but the wire only had one strand left that was connected, not enough to send a signal back to the ecu.
 
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